From e3117404b41124c88a4d834fc3222669a880addc Mon Sep 17 00:00:00 2001 From: Matthew Maurer Date: Tue, 20 Aug 2024 19:48:58 +0000 Subject: [PATCH] kbuild: rust: Enable KASAN support Rust supports KASAN via LLVM, but prior to this patch, the flags aren't set properly. Suggested-by: Miguel Ojeda Signed-off-by: Matthew Maurer Reviewed-by: Andrey Konovalov Link: https://lore.kernel.org/r/20240820194910.187826-4-mmaurer@google.com [ Applied "SW_TAGS KASAN" nit. - Miguel ] Signed-off-by: Miguel Ojeda --- scripts/Makefile.kasan | 57 ++++++++++++++++++++++++--------- scripts/Makefile.lib | 3 ++ scripts/generate_rust_target.rs | 2 +- 3 files changed, 45 insertions(+), 17 deletions(-) diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan index aab4154af00a..693dbbebebba 100644 --- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -12,6 +12,11 @@ endif KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET) cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1))) +rustc-param = $(call rustc-option, -Cllvm-args=-$(1),) + +check-args = $(foreach arg,$(2),$(call $(1),$(arg))) + +kasan_params := ifdef CONFIG_KASAN_STACK stack_enable := 1 @@ -41,39 +46,59 @@ CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \ $(call cc-option, -fsanitize=kernel-address \ -mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET))) -# Now, add other parameters enabled similarly in both GCC and Clang. -# As some of them are not supported by older compilers, use cc-param. -CFLAGS_KASAN += $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \ - $(call cc-param,asan-stack=$(stack_enable)) \ - $(call cc-param,asan-instrument-allocas=1) \ - $(call cc-param,asan-globals=1) +# The minimum supported `rustc` version has a minimum supported LLVM +# version late enough that we can assume support for -asan-mapping-offset. +RUSTFLAGS_KASAN := -Zsanitizer=kernel-address \ + -Zsanitizer-recover=kernel-address \ + -Cllvm-args=-asan-mapping-offset=$(KASAN_SHADOW_OFFSET) + +# Now, add other parameters enabled similarly in GCC, Clang, and rustc. +# As some of them are not supported by older compilers, these will be filtered +# through `cc-param` or `rust-param` as applicable. +kasan_params += asan-instrumentation-with-call-threshold=$(call_threshold) \ + asan-stack=$(stack_enable) \ + asan-instrument-allocas=1 \ + asan-globals=1 # Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*() # instead. With compilers that don't support this option, compiler-inserted # memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures. -CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1) +kasan_params += asan-kernel-mem-intrinsic-prefix=1 endif # CONFIG_KASAN_GENERIC ifdef CONFIG_KASAN_SW_TAGS +CFLAGS_KASAN := -fsanitize=kernel-hwaddress + +# This sets flags that will enable SW_TAGS KASAN once enabled in Rust. These +# will not work today, and is guarded against in dependencies for CONFIG_RUST. +RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress \ + -Zsanitizer-recover=kernel-hwaddress + ifdef CONFIG_KASAN_INLINE - instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)) + kasan_params += hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET) else - instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1) + kasan_params += hwasan-instrument-with-calls=1 endif -CFLAGS_KASAN := -fsanitize=kernel-hwaddress \ - $(call cc-param,hwasan-instrument-stack=$(stack_enable)) \ - $(call cc-param,hwasan-use-short-granules=0) \ - $(call cc-param,hwasan-inline-all-checks=0) \ - $(instrumentation_flags) +kasan_params += hwasan-instrument-stack=$(stack_enable) \ + hwasan-use-short-granules=0 \ + hwasan-inline-all-checks=0 # Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*(). ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y) - CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1) + kasan_params += hwasan-kernel-mem-intrinsic-prefix=1 endif endif # CONFIG_KASAN_SW_TAGS -export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE +# Add all as-supported KASAN LLVM parameters requested by the configuration. +CFLAGS_KASAN += $(call check-args, cc-param, $(kasan_params)) + +ifdef CONFIG_RUST + # Avoid calling `rustc-param` unless Rust is enabled. + RUSTFLAGS_KASAN += $(call check-args, rustc-param, $(kasan_params)) +endif # CONFIG_RUST + +export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE RUSTFLAGS_KASAN diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index fe3668dc4954..27999da3d382 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -167,6 +167,9 @@ ifneq ($(CONFIG_KASAN_HW_TAGS),y) _c_flags += $(if $(patsubst n%,, \ $(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \ $(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE)) +_rust_flags += $(if $(patsubst n%,, \ + $(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \ + $(RUSTFLAGS_KASAN)) endif endif diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs index 087c1d13d33b..0d00ac3723b5 100644 --- a/scripts/generate_rust_target.rs +++ b/scripts/generate_rust_target.rs @@ -207,7 +207,7 @@ fn main() { } ts.push("features", features); ts.push("llvm-target", "x86_64-linux-gnu"); - ts.push("supported-sanitizers", ["kcfi"]); + ts.push("supported-sanitizers", ["kcfi", "kernel-address"]); ts.push("target-pointer-width", "64"); } else if cfg.has("X86_32") { // This only works on UML, as i386 otherwise needs regparm support in rustc